On July 6, 2026, between approximately 18:34 and 19:19 UTC, some requests to our MCP server (used by MCP-powered integrations to access Buffer’s public GraphQL API) returned HTTP 404 errors. This issue was limited in scope to the MCP server pathway; the primary public API at https://api.buffer.com and other Buffer services continued operating normally. We did not receive any customer reports during the incident window.

The issue was triggered by a deployment related to our GraphQL server migration, which changed how strictly the API validated request paths. The MCP server was calling the GraphQL API using the /graphql path, and the new configuration only accepted requests at the root path (/), causing those MCP calls to fail. We mitigated the incident by rolling back the change, restoring normal behavior, and then completed follow-up work to support GraphQL on both / and /graphql while aligning documentation and adding coverage to reduce the risk of similar endpoint-contract regressions in the future.